Terminal blocks are commercially available for modular plug-together electrical wiring systems suitable for installation in the wire way or raceway of a space dividing panel. One commercially available terminal block, such as that shown in U.S. Pat. No. 4,634,212, which is assigned to the same assignee as the present application, has first and second sockets at each end for receiving connectors of electrical cables, and first and second cavities or sockets on opposite vertical faces or sides for receiving plug-in duplex receptacles. The plug-in receptacles have rear mounted conductor blades which make contact with energized, neutral, and ground conductors in the terminal block, when the receptacle is plugged into one of the side mounted socket cavities.
The first and second sockets at each end of the terminal block are both utilized only when the electrical circuit branches from one panel into two or more additional panels. Otherwise, only one end socket is utilized. Cavities having openings for receiving conductive blades of duplex receptacles are provided on opposite sides of the terminal block so that duplex receptacles may be plugged into the cavities, making duplex receptacles available for use on both sides of the associated space dividing panel, as required.
When two duplex receptacles are required on a side of a space dividing panel, two terminal blocks are provided in the panel with an electrical cable extending between the two terminal blocks. This necessitates the additional cost of a terminal block and electrical cable, as well as the cost of providing mounting means for two terminal blocks in the raceway.
It would be desirable, and it is an object of the present invention, to be able to have two duplex receptacles per panel side, when required, utilizing a single standard commercially available terminal block for receiving side mounted duplex receptacles. This object must be achieved without extension of the receptacles beyond the external face of the associated raceway cover by more than the conventional fraction of an inch. In other words, a quadplex which would simply plug into the duplex receptacle is not desirable because the whole quadplex would be external to the raceway cover, detracting from the appearance of the installation, as well as presenting a bumping problem for vacuum cleaners, and the like. The external quadplex approach would also add an additional frictional electrical connection between the device plugged into the electrical system and a terminal block, increasing electrical losses.